I have different Orbs in the game. How do they differ?

Green Orbs of protection are generally good choice for standard adventuring, since their additional defense bonuses help you mitigate the nicks and cuts you will sustain while fighting enemies.
You should stock up with the Red orbs of striking if you prepare for the big fight. These orbs could increase the damage of your hits and it is necessary in battle with the strong and danger enemy.
Orbs could be minor, general and large. The bigger orb you have, the more powerful and useful it would be.